Stephen Sondheim sits down with Frank Rich

The co-creator of modern musical classics including “Gypsy,” now previewing in its latest Broadway revival, and “Sweeney Todd,” which just arrived at the Ahmanson, opined on his career and the state of the art with the New York Times’ Frank Rich in UCLA’s Royce Hall on Thursday night.

A protege of the late librettist, Sondheim assisted on Hammerstein’s third show with Richard Rodgers, “Allegro.” “It was wildly ambitious and didn’t work — and I’ve been following that same pattern ever since,” Sondheim reported with a grin. “I’d love to have a long-running smash hit, but it’s unlikely.”

Like Hammerstein, whose “Show Boat” was experimental in its day, Sondheim has readily risked audience and critical disfavor. “I like structure and order, and then I like to see how far I can push them,” he said, citing the half-book/half-revue nature of “Company” and the fusion of Japanese and Western conventions in “Pacific Overtures.”

“Some of my shows even have a happy ending,” he added. “Well, a few.”

The UCLA talk began as if in mid-conversation, the speakers (introduced as “the Beauty and the Beast of Broadway”) having just arrived from a similar San Francisco event. The old friends’ easy banter included Rich’s reminder to include last names when discussing “Arthur” (Laurents) and “Lenny” (Bernstein), and Sondheim’s occasional “I don’t know if I ever told you this.”

Inspired by the L.A. setting, Rich encouraged Sondheim to weigh in on his disdain for stage-to-Hollywood adaptations. “Film is a reportorial medium, while theater is a poetic medium,” he asserted, explaining that the stage is better suited to uninterrupted song sequences in which the aud’s imagination is in play.

Sondheim made a pointed exception of Tim Burton’s “Sweeney Todd,” praising its “swiftness and tension.”

“It’s scaled down,” he added. “Everything is intimate, with film noir performances.”

The assembled cognoscenti most enjoyed shared insights about legendary colleagues Jerome Robbins (“paranoid” but “a genius — endlessly inventive”) and Michael Bennett, with glimpses into the creative process behind Robbins’ rescuing of “A Funny Thing Happened on the Way to the Forum” with the addition of the “Comedy Tonight” number and Bennett’s work on the mirror number, “Who’s That Woman?,” from “Follies.”

Sondheim remembered divas as well.

He recalled Ethel Merman’s rebuke to Jerry Orbach in “Annie Get Your Gun” for too obviously reacting during speeches: “Listen, you don’t react to me and I won’t react to you!” And he discussed how the blowsy Joanne of “Company” was modeled on originating thesp Elaine Stritch. “Back in her boozing days,” Stritch made a 2 a.m. arrival in a Broadway nitery, delivering this memorable line to the bartender: “Gimme a fifth of vodka and a floor plan.”